Brain cells and neuroglia. Illustration of a human brain (lower left) and nerve cell types and anatomy (inset, upper right). The main cells are neurons (blue), which consist of a nerve cell body, and a projection known as an axon. Axons conduct electrical impulses away from the neuron's cell body. The myelin sheath (pink, partially shown) of the axons aids the electrical conduction. Support cells (neuroglia) are also shown: oligodendrocytes (green) and astrocytes (pale blue). Oligodendrocytes provide support and insulation to axons. Astrocytes, which have a large number of functions, are subdivided into fibrous and protoplasmic types. Protoplasmic astrocytes are found in the brain's grey matter, and have relatively short processes attaching to neuron cell bodies. Fibrous astrocytes (in the white matter) have much longer processes and attach to axons. For this artwork without labels, see C030/3211.